thumb|right|300px|8-cell embryo for transfer in [[in-vitro fertilization]]
Embryo space colonization is a theoretical interstellar space colonization concept that involves sending a robotic mission to a habitable exoplanet or other viable target for terraforming transporting frozen early-stage human embryos or the technological or biological means to create human embryos. The proposal circumvents the cost and scale demands of other interstellar colonization concepts.
Various concepts
Embryo space colonization concepts involve various ways of delivering the embryos from Earth to an extrasolar planet around another star.
- The most straightforward concept is to make use of embryo cryopreservation. Modern medicine has made it possible to store frozen human embryos in various low-development stages (up to several weeks into the development of the embryo) for decades or more.
- Another scenario would use in vitro fertilisation to create human embryos from frozen sperm and eggs, all likewise well established technologies.
- Far more speculatively, artificial gene synthesis could be used to abiogenically construct DNA with nonliving material, reproducing genes from purely digital computer files of individual humans' whole genome sequencing, for implantation into a natural or artificial cell, creating a live human zygote 'from scratch'. This scenario would also allow self replicating machines to spread humanity arbitrarily far with absolute minimal physical payload.
Mission at destination
Regardless of the cargo used in any embryo space colonization scenario, the basic concept is that upon arrival of the embryo-carrying interstellar starship at landfall, fully autonomous robots would build the first settlement on the planet and start growing food. More ambitiously, the world may be terraformed first. There is a 14-day rule, codified into law in twelve countries, preventing human embryos from being kept in artificial wombs past 14 days.
- Long-duration computers: Computer hardware would need to function reliably over long periods of time, in the range of several thousands of years for current day propulsion.
- Propulsion: Furthermore, a propulsion system would be required that could accelerate the embryo ship to a high speed and slow it down again upon nearing the destination. Even assuming a speed one hundred times faster than any of today's space probes and a target planet within a couple of hundred light years would lead to a journey lasting several thousands of years.
- Exoplanet found: Finally this depends on the existence of an exoplanet qualifying for colonization within a reachable distance, or other resources capable of sustaining the construction of some other settlement. Current or future science missions like the Hubble, James Webb, or TESS space telescopes may very well yield results for this requirement in the near future.
Further unknowns that affect the feasibility of embryo space colonization are:
- Biological: Will genetic material survive intact on a space mission that could potentially last centuries? Exposure to cosmic rays is known to irreparably damage DNA. What other symbiotic lifeforms does a human need to live a healthy life? For example, gut flora and many other species of microorganisms may be necessary for proper biological and immunological functioning. Babies normally acquire these from their mothers and the wider environment, but this would not be the case for embryos in colonization ships. Aside from humanity, how many and which other species from Earth should be introduced into this new ecosystem, especially depending on how much terraforming is needed?
- Ethical: In addition to the question of whether it is technically feasible to raise children without human contact, there is the further question of whether this is morally permissible. It is found to be unethical to deliberately create children that will grow up without parents, yet embryo space colonization requires this. Controversial value judgments would also need to be made about whose DNA should be the basis of the space colony. Should they be selected by some metric of merit, or randomly from the general population? Either choice presents ethical problems. Should the parenting AI firmly steer the children to maximize the chances of the colony's success, or should it accept the risk of allowing them significant autonomy? Which languages and cultural values should be transmitted to the colonists? Should they be raised according to some value system that exists on Earth, or create one that is somehow optimized? Are there truths that should be kept from them? The possibility of a new civilization that starts without a cultural legacy might appeal to cults that want their values to become a norm for an entire society. Is it permissible to allow them to have their own embryo colonies, where the AI indoctrinates the colonists only in the cult's value system? The difficulty of answering these and other ethical questions may become a non-technological obstacle to embryo space colonization.
See also
- Embryogenesis
- Uploaded astronaut